The present invention relates generally to security screen systems for windows and doors in both residential and commercial buildings.
Known security screen systems consist of a sensing wire woven into or bonded to the fabric of an existing door or window screen and connected to a suitable circuit for detecting if the screen is cut or removed and for activating an alarm if this occurs. These systems are subject to some disadvantages in that the copper sensing wire can become corroded as a result of exposure to the external environment, resulting in malfunctions. Also, the wire can sometimes be stretched enough to allow an intruder to open the window or door without activating the alarm. Additionally, such screens are sensitive to electromagnetic interference which can give false alarms, and can be bypassed relatively easily by someone with an elementary understanding of electricity and circuits.
Other security panels incorporating optical fibers have been proposed in the past. These panels may either be specially constructed, or are formed by gluing or interweaving a plurality of optical fibers onto an existing screen or panel, with an optical emitter and detector at the opposite ends of each fiber. Alternatively, additional lengths of optical fiber are used to bring all the spaced fiber ends to a common source and detector location. Both these arrangements are relatively complex and therefore expensive.